Process of making smokeless explosives



2 Sheets-Sheet 1 L No Model.) v

,1 2. G. an P. s. DU PQNT; y PROCESS OF MAKING SMOKBLESS EXPLOSIVBS.10,503,585

Ptented Aug. ZZA, .1893.y

` P776 dal@ (No Model.) 2 Sheets-'Sheet 2.

lF. G. 5 12.5. DU PONT. PROCESS 0F MAKING SMOKELESS EXPLOSIVES.

150,503,585. A K B55551155 Aug. 22, 189s.

Unirse Sterns FRANCS DU PONT AND Para @restent PIERRE S. DU PON", Ol*iVlLMlNG'lTlN,

DELAWARE.

PRGCESS OF iillAKlilG SMOKELESS EPLSiJ-ES.

ECIFICATON vformingpart o' Letters Patent No. 503,585 dated August 22,1893.

Application tiled March 17, 1893. Serial No. 466,488. (No specimens.)

To @ZZ 'whom it may concern:

Beit known that we, FRANCIS G. DU PONT and PIERRE S. DU PONT, citizensof the United States, residing at iVilmington, in the county of NewCastle and State of Delaware, have invented certain new and usefulImprovements in Explosives; and We do hereby declare the flollowing tobe a full, clear, and exact description of the invention, such as willenable others skilled in the art to which it ap` pertains to make anduse the same.

Our invention relates to improvements in explosives which areparticularly adapted for imparting a high initial velocity to theprojectiles of small bore riies, such as the Man n.- licher, thelrag-Jorgensen and the English 303, and it consists in an improvedprocess for producing an explosive from nitro-cellulose, consisting ofgranulating the nitro-cellulose by agitatiug therewith, when suspend edin a fluid, a solvent ot the saine in suitable proportions, which willbe hereinafter fully described, and particularly pointed out in theclaims. v

The main object of our invention is to prod ucc an explosive which willbe smokeless, or nearly so, which will be unaffected by being kept for aconsiderable space of time, which, high muzzle velocity to the the gunbarrel at the moment ot firing, and which can be eas-ily and safelyhandled and vrstored. Our invention has for its special aim,

however, the attainment of a higher'initia-l velocity than has formerlybeen attainable by the use ot'smokeless explosives, with the aim ofadapting the explosive to use with small bore rifles, such as thosementionedabove.

lu our application for Letters Patent forA improvements-in explosives,filed December' 21,1392, Serial No. 455,001, we described a process forproducing smokeless powder, the distinguishing feature of which was thegranulation of pure nitro-cellulose by mixing therewith a solvent of theseme iusuitable proportions. Basing our process on the tendcncy which Wefound was inherent in the various solvents of the nitro-celluloses, andespecially the nitro-derivatives of thcaromatic group, when mixed in aiiuid in which finely divided nitrocellulose is suspended, to seize thenitro-cellulose and leave the Water clear,

forming in thewater a more or less coherent mass, we discovered thatwhen the solventis., added in proper proportions, (and we found that theproportions of three parts of the and forming a coating around the same.These grains,after they have undergone a process of hardening byrotation in a barrel, and removal of excess ofsolventl and watercontained in the grains by boiling, or. by rotation in a barrel in anatmosphere of steam, in which case the removal of the excess of solventand Water contained in the grains Will take place at the saine time asthe rotation, become sut'iiciently rm to be graded as to sizepreparatory to being placed on the marhet, and constitute a valuablesmokeless powder, the violence of whose explosiveaction can bediminished by varying the duration of the above processes, or it maybe-still lfurther diminished-by the addition of a substancdto Amoderateitsvaction. We have found nitrated rosin and citi-ated turpentineespecially suited forthis purpose, and we add them in the manner andproportion stated iu said application. We have discovered, however; thatincreased hardness and consolidation of the grains thus formed may beobtained by subjecting th z grains, either directly after they have beenremoved from the churn in which they were formed, or .after they havebeen subjected to partial treatment by rotatior iu an atmosphere ofsteam in order to remove" the excess of solvent, to the action' of lagentle heat, not suilicieut to cause vaporization of the solvent, but toremove some ef the yvavter condensed in the grains, thisl discover-,vbeing based upon the property, which we have found the Vgrain possesses,of giving/up. its

contained water before it parts with the solv- Y ent used in itspreparation, and at a lower heat.

In the drawings accompanying and form- ICO- v rior at' the churn enedand prepared 5 imity to the bulkhead flzof the barrel.

sented the apparatus which we use in carrying out our process, Figure l,which is taken on the line'rcfc Fig. 1,lookingin thedirection of thearrow, illustrating the churn in which the mixture of thenitro-cellulose with the solvent takes place;"1"ig. 1n being a sectionalview of the same; and Fig..2 being a representation of therotatingbarrel in which the grains formed in the churn shown in Fig. l arehardened and rounded, and thustitted for use. It is taken on the line yy Fig. 2". Fig. 2 is a view taken ou the line .a' .z Fig. 2, looking inthe directionof the arrow. It shows the double series ofapertures-infime inner bulkhead of the barrel, and Tsd the series ofcycioidal chutes which conduct the water of condensation, receivedthrough the the bulkhead, to pipe forming the the said water is outerseries of apertures in the apertures in the central axis of the barrel,by which conveyed away.`

' Before proceeding with a description of our process, we Awilldescril-e the apparatus used in carrying it out.

Referringv to Figsx] and l, A represents a churn, in which, by a shaftl, are rotated the blades b, each of which is formed with a notchedouter surface to promote currents from side to side in the contents ofthe churn during rotation. Steam inlet pipes C are provided' whicharerelativelysmall in diameter, so that the steam will be welldistributed through the contents of the churn,and a singie steam outletpipe D, which leads to the refrigerating coils E, where the vapors whichit conducts may be condensed. `An opening F is provided forthe-admission of material, and an opening C when desired. Test cocks l lare also provided, in order that the condition of the contents of thcchurn may at any time be inspected.

In Figs. 2 and 2, the rotating barrel is represented in which the grainsof explosive produced in the churn just described are hardfor use. Thisbarrel, II, is provided with a tubular axis I, journaled in the supportsi, to which axis steam is con- ,ducted by the pipe 2, and from whichsteam is conveyed away by the pipe 8. 'This barrel is designed tofacilitate the escape of 'both water and steam, the latter carrying oifthe solvent used, and to this end is formed with an innerbulkheadK,which is placed in close prox- In this inner bulkhead are formed twoseries of apertures, one around its periphery S, for the ,separation ofwater from the contents of the barrel, and que nearits center 9, for theescape of steam from the same. Between the two bulkheads K and K arearranged a- .scries of cycloidal chutes or guides` L, ail ot whichconverge toward `the central axis. In the operation of the barrel, steamis admitted to its interior through the aperture f' in the central axis,passing outthrough thc apertures 9 in tho bulkhead K, from which itpasses to aid in ushing the inte.

4solvent of great extent in the liquid uscdto suspend.

through the axis I and the pipe 3. W'atcrof conde sation, as fast asformed, and also the water separated. from thc grains ot' explosive,passes through the outer' series ot' apertures in the bulkhead K at thelower part of the revolution of the barrel into the space botween thesaid bulkhead K and bulkhead K", and is conducted by the cycloidalchutes towaid the axis of the barrel, then passing fout through theapertures 6 formed at this point.

Proceeding now with our process, we place inl-the churn A about ninetyliters of Water, or other liquid, whichl may either be pure, or mixedwith any salt. When w'ater is used, we sometimes dissolve ci um, commonsalt, saltpeter or other salt, as we can thus modify in many ways thecharacteristics of the grains formed. We addto the water about sixkilograms ot gun cotton, beating it up with the water in the churn untila thorough mixture has taken place. When this has been accomplished, weadd to the mixture nitro benzole, or other. suitable gun cotton notmiscible to any nitro-toluol and nitroabout three times the the guncotton, such as xylol, to the extent of weightot the gun cotton. tion ofthe contents of. the churn is continued, the gun cotton assumes awell'detined granular state, the grains formed, being soft" andcontaining considerable water. .During this agitation. steam may beadmitted through the bottom of the churn,an'd this as it passes outthrough the refrigerating coils `carries with it a portion of thesolvent, which is ro-l coveredin the said'coils. This action of thesteam is not, however, essential to ,they production of the grains,though it assists in their formation, and may be omitted withoutdetriment to the product., The 4sire of the grains may be varied bychanging the proL.

portions ofthe ingredients and thefduration.

of treatment. Tho-above is an example'of proportions which give goodresults. Instead of placing the grains thus forined'direct'ly into therotating barrels shown in Figs. 2 and 2, and rotating said barrel withingress of steam until theexcessof volatile solventhas been entirelyevaporate'tfrom the grains, as we doin the process described in theapplica.` tion for Letters Patent for improvements in explosives alreadyreferred to, we have found that better results as to the hardness andd'egree of consolidation of the resulting grains may be obtainedhysubjectingthe grains lto a gentle heat,'ranging say from 120 to 180l-`ahrenheit, either placed in the rotating barrel, or after they havebeen partiz'tllytreated in the saine. This result is due to apropertywhich 1the grains possess of parting with the water condensed in theirfiber before they part with the Solv? ent used in tlicir preparation.liy heating tle said grains to afpoint not sufficient to carry away tnosolvent, but only to evaporate When the agitabefore thehgrains are in itchloride of cali the condition of thegrains and consolidation required,the grain is vin the steam cess for ivhich application for 'Cotton inthe dense, and thus become tted to produce the high initial `velocity tothe projectile which is the object of this'process. It is not Vmaterialwhether the grains be subjected to this gentle heat before they havebeen treated by boiling for removal of excess of solvent, or

after they have been partially so treated, it only being necessary thatthey be so treated before the outer envelope of the grains becomes sohard as not to permit the passage of Water through the same.

We do not confine ourselves to the temratures mentioned, although we ndthem good for the purpose intended, nor do we coniine ourselves to anyparticular method of exposing the grains Ito heat, using a rotatingdriersueli as is used in sugar refineries, or spreading the grains uponsieves, or adopting any other method for the desired purpose.

After this roasting process has been carried to a greater or lessextent, dependent upon the degree of treated in the sblvent being boiledott the usual manner,

a still, or in the barrel, or in open air.

We .have found that better results are obtained in the use of the barrelby creating a vacuum atA the steam outlet pipe, as the vapors arethereby more rapidly conveyed away,

and the amount of time required for the treatment in the barrel isreduced.-

The explosive force of the explosive thus produced maybe tempered in thesame manner as was the explosive produced by our pro- Letters Patent hasalready been made, namely, by adding from two and one-halt per centi toten per cent. of a inoderatingagcnt, such asnitrated rosn or nitratedturpentine, 'e'. c., rosin or `v'cnice turpentine treated with nitricacid, although wc do not conline ourselves to the use of thesesubstances, nor to the proportions mentioned. We add`this moderatingagent by dissolvingthe saine in the solvent used in the granulationprocess, or by adding it to the finished grain, or in any other suitablemanner, but' it must be added in the proportion which it is to bear tothe finished proj duet as it is non-volatile at thc tenipcratuics used.

We have described thegun cotton as being.'` diilusedin water, but it isevident that an) other (luid, which will cause a better, or as good adistribution ot the particles of gunchui'n may be used instead; and

while gun cotton has been described as the- Lform of nitro-celluloseemployed in the process, it is evident that other formsofinitrocellulose may beused instead if desired.A

-We do not confine ourselves tof the exact4 proportions mentioned, norto the particular apparatus described, as these .can bevat-led andchanged without affecting the merits of our process.

What we claim as new, and desire to secure f by Letters Patent, is-

1. The herein described process for producing a smokeless explosive,which consists in suspending nitro-cellulose in a liquid not a solventof the saine,'granulating the nitrocellulose by agitati n g therewith inproper proportions a suitable'solvent of the saine not miscible to anygreat extent in the liquid used to suspend the nitrocellulose, and so!lidifyingthe grains thus formed by subjecting the saine to a heatinsufcient to vaporize the solvent but sutiicient to vaporize the liquidfor removal of the liquid contained in the grains, and vthen removingthe excess of solvent, substantially as described.

, boiling them for nitro-cellulose,

- portions a 2. The herein described process for producing a smokelessexplosive, wl'iich consists i'nsuspending nitro-cellulose in a liquidnot a solvent of the same, gran'ulating the nitrocellulose byagitatingjtherewith in proper p'roportions asuitable solvent notiniscible to any great extent in the liquid used to suspend theandsolidifyin g the grains thus formed by subjecting the saine to a heatin= sufficient tf' vaporize the solventabut Sullicient to vaporize theliquid tor removal ofthe liquid contained in the grains, and then to aheat sufiicient to vaporize the solvent for removal ofA the excess ofsolvent, substantidarly as described.

3. The liereindcseribed process for producing a smokeless explosive,which consists in suspending nitro-cellulose in a liquid not a solventof the same, granulating the nitrocellulose by agitatirg therewith inproperprol portions a suitable solventnot miscibletoauy great extentinthe liquid used to suspend the nitro-cellulose, and solidifying thegranstiis formed with removal of liquid contained in the saine andexcess of solvent by s .-bjeetingu them toaheat ranging from to 180Fahr-f enlieit for removal et the liquid, and then removal of excess ot'solvent,- substantially as dcscrilvedf,A f L 'lhe herein describedprocess for producf ing a smokeless explosive, whic'nconsists in tog IKO

susnending nitrocellulose iii-'a liquid vnot a solvent of the same,gra-nulating the nitrocellulose by agitating therewith in properprosuitable solvent not iniscible to any great extent in the liquid usedto suspend the nitrocollnlose, and soldif ying the grains thus formed bysubjecting the same'to'aheat insul'lcient to vaporzc Vthe solvent but'-suili cient to vapori/.c the-.liquid forri'gmovalof the liquid containedin heut sullieicni to vapor-izo thcsolve'nt for rcthc-grains, and 'theirto ai moval of the excess of solvent, the latter opsolvent butsufficient to vaporize the liquid eration being.,r accompanied byagitation, subfor removal of the liquid contained in the 15 stnntially'as described. grans,'and thenrotating the grains iu an at- 5. The hereindescribedprocess for producmosphere of steam forv removal of the excess5 ing as'rnokeless explosive, which consists" of soivextsubstnntinlly asdescribed. v suspending nitro-ce11ulosefin a liquidv not a' f5' Intestimony whereof we ax our signatures sofelnt of the same, granulaltiugthe nitro- 'in pesenceof two witnesses. ce u ose by agitating t xerewit1 in proper proportions n, suitable solvent of the samenot r' xotmiseible to any great extentin the liquid used to suspend thenitro-ceiluose, and solidify` Witnesses: ing` the grains thus formed bysubjecting the HENRY J. CRIPPEN, same to a heat insufficient to yaporizethe` FRANCIS II. IIOFFECKER.

